Relief - all this is studied today at school in geography lessons. Knowledge of these topics is necessary not only for passing the exam, but also for general development. After all, each of us must understand what the surface of the planet on which we live is.
North America, the relief of which we will consider in this article, resembles South America in the type of vertical dissection. A powerful belt stretches along the western coast for 7000 km. The eastern half of this mainland is predominantly flat. All this allows us to say that the relief of North and South America has a significant similarity. However, there are significant differences between these continents. In particular, the Cordillera as a mountain system is much wider and more complex than the Andes (also called the Andean Cordillera). They consist of a whole system of ridges that differ in tectonic and geological structure, which are isolated.
Eastern Belt
5 orotectonic longitudinal belts are clearly distinguished almost along the entire length of the Cordillera. The first of them, the eastern one, is the ranges of the Laramian folding: the Mackenzie Mountains, the Brooks Range, the Eastern Sierra Madre Range, the Rocky Mountains. The latter can be divided according to the features of orography into two parts: southern and northern. Between them, the Yellowstone Plateau acts as a border. The clear straightness of forms is a striking orographic feature.
Front Range of the Rocky Mountains
The front range of the Rocky Mountains (North America) has the following relief: it stretches for almost 2000 km in a straight line, striking with the continuity, integrity and uniformity of its geological structure. The mountain range, distinctly expressed, is crowned with steep high peaks, the height of which reaches 4000 m. It gradually descends in the east to the Great Plains. The front range in the west is limited by a tectonic fault in the northern part. In the middle part of the mountain are lowered. They are crossed by the Peace River, which is one of the sources of the Mackenzie River. The front range in the southern part is expanding. It is divided into separate ranges, the height of which is significant: Lewis, Caribou, Selkirk. In this part, the largest peaks of the Front Range are located. These are Mount Robson (height 3954 m) and Mount Columbia (3747 m). Alpine landforms North America typical of the Front Range. It is also characterized by impassability and significant glaciation.
Rocky mountains in the south
The Rocky Mountains do not form a single mountain range in the southern part. Here they consist of separate massifs, sometimes isolated and separated by "parks" - wide basins, which are plateau-like areas that connect the Great Plains with the Great Basin. Some of the ridges (Sangre de Cristo, Wasatch) stretch almost from north to south. Others (for example, Yuinta) - in a west-east direction, perpendicular to them. The significant height and width of this mountain belt compensates for the lack of continuity. The border between and the Rocky Mountains is very clearly defined: a steep wall is a mountain slope. The southern segment is typical epiplatform mountains, which were formed after the activation of the edge of one of the ancient platforms.
Belt of internal plateaus and plateaus
The next is a belt of internal plateaus and plateaus formed in the Nevadian folding on the mainland of North America. The relief is characterized by folded Nevadian structures represented by peniplains. Within this belt there are also plateaus that are confined to the "fragments" of the ancient North American platforms and are sandwiched by the Cordillera ridges (Northern Mass, Colorado Plateau). The largest intermountain plains: Fraser, Yukon, Great Basin, Columbia, Northern and Central Mass, Colorado.
Big Pool
The Great Basin is a denudation plateau, the largest in area. This territory, the width of which reaches 800 km, as a whole is an alternation of plain and mountainous surfaces, with the former predominating. On average, the surface of the plateau is raised by 1500 m. However, the height fluctuations are large. The plateau is crossed by parallel ridges with heights of about 3 km (Wheeler Peak - 3982 m). Deep depressions called bolsons lie between them. These are semi-closed and closed basins, which are areas of internal runoff. Death Valley is one of them (-85 m).
Remnant peaks are often found here (including the cones of volcanoes).
Colorado Plateau and Grand Canyon
This is one of the unique corners of our planet that North America is famous for. Its relief is very beautiful. In its geological structure (undisturbed horizontal plates of sedimentary rocks of different ages - from the Upper Paleosian to the oldest, lying on a crystalline basement), this plateau is similar to the North American platform. Its surface is a hilly plain, the height of which reaches 3860 m.
The attraction of the plateau is the Grand Canyon (North America). The relief and climate attract many tourists to this place. The Grand Canyon (pictured below) was formed along the Colorado River, in its middle reaches. Its depth reaches 1800 m, with a width of 8 to 25 km at the plateau level and up to 1 km at the bottom level. Steep slopes of an interesting, bizarre shape are characteristic of the Grand Canyon. They arose as a result of processes of erosive destruction and weathering. A winding narrow channel is cut into the crystalline base.
Inner mountain belt
The third belt - the inner mountain - is the belt of the Nevadian ranges: the Coast Range, the Alaska Range, the Cascade Mountains, the Sierra Nevada, the Transverse Volcanic and Western Sierra Madre. These mountain ranges are distinguished by straightness. Igneous rocks predominate in their structure. - a batholith with volcanic cones impaled on it. The Sierra Nevada Range is an asymmetric giant crystalline batholith with gentle western and steep eastern slopes.
Synclinorium belt
The fourth belt is the synclinorium belt. This is a zone of subsidence, which took shape in the Neogene. Part of it is currently represented by various sea bays and straits. On land, this is Death Valley, the Great California Valley, the lower reaches of the Colorado River.
Extreme western belt
The fifth belt is the extreme western one. This is the coastal belt of such ranges as the Aleutian (there are 25 active volcanoes), the Kenai Peninsula, the Island Range with Victoria Peak (altitude - 2200 m), the Chugach Range, the Victoria Peninsula, the Coast Ranges, the South Sierra Madre Range. All of them are medium-altitude, only the most prominent peaks are higher than 2 km.
Depending on the degree of glaciation, the severity of orographic longitudinal belts, tectonic and erosional dissection, the Cordilleras are divided into 4 morphostructural regions: the Cordillera of Mexico, the Cordillera of the USA, the Cordillera of Canada and the Cordillera of Alaska.
Eastern part of the mainland
What is the relief in North America in the east? Let's figure it out. As we have already noted, the landforms of North America are mostly flat in the eastern part of the mainland. Basically, these are elevated (Central, Laurentian) and high plains. The low-lying ones are located along the coastline: the Mexican, the Atlantic, the Gudson, and also the Mississippi in the lower reaches of the river of the same name.
Appalachian mountain belt
In North America, unlike South America, another mountain belt stretches along the east coast - the Appalachian. This is a system of mountain ranges located from the Gulf of St. Lawrence to about 33-32 0 s. sh., that is, almost 2300 km. is the northern link. The Appalachians are epiplatform mid-altitude mountains. A significant difference between the southern and northern parts of this mountain system determined the features of the tectonic and geological structure. The Hudson Graben is the boundary between the Southern and Northern Appalachians. The northern Appalachians as a whole are undulating plateaus. Individual mountains, ridges or mountain ranges rise above it. The northern Appalachians were covered by the Quaternary glaciation. Therefore, the shapes of the mountains now are gentle, only on the highest peaks there are circuses with sheer walls.
Southern Appalachians
The Southern Appalachians are distinguished by the alternation of long parallel valleys and ridges. Plateaus stretch along the foot of the mountains from the east and west. This is Piedmont in the west - a denudation flat plain, which is formed by the Early Cambrian crystalline rocks. From it, in the west, a chain of mountain ranges rises steeply, almost continuous (Kokhuta, Unaka, Cherny, Smoky, Bolshoi, Blue, etc.), the height of which is 1-1.5 km. These are "ancient mountains" - dense cores of Caledonides, dissected by denudation.
Belt of ridges and valleys
One of the most remarkable regions of the Appalachians is located to the west of them. These are the so-called Young Mountains, or the Belt of Ranges and Valleys. Here are some interesting features of the relief of North America. The entire territory is composed of sedimentary rocks of the Paleozoic times: ridges - shale and sandstones, valleys - dolomites and limestones. Elongated for hundreds of kilometers from the southwest to the northeast along the line of the strike of the mountains, wide valleys alternate with flat-topped or narrow ridge-like ridges. At an altitude of 500-600 m lies the bottom of the valleys. The tops of the ridges reach 1-1.2 km. Valleys in tectonic terms are anticlinoria, and the ridges are synclinoria. That is, in this place there is a clear discrepancy with the type of tectonic structure of the modern form, which the relief of North America has here. A photo of the Appalachians is presented below.
This is an example of an inverted or inverted terrain type. It is quite rare in the mountains and is most pronounced in the Appalachians. This type of relief, by analogy, became known as the "Appalachian relief". The belt of "young mountains" interrupts the Appalachian Plateau (Cumberland, Allegheny) from the west. It is a ledge, the height of which is 300-400 m. This plateau is significantly higher than Piedmont. Its surface at the eastern edge lies at an altitude of about 1.2 km, and at the western edge - 500 m. The plateau is deeply dissected in places by valleys of various rivers (gorges with narrow bottoms and steep slopes).
Well, now that the relief of North America has been briefly discussed in this article, we hope it will be easier for you to form your own idea about it.
The relief of North America represents all the diversity possible on the planet. Here are sultry deserts, and many meters thick ice of the Arctic, impenetrable virgin forests and volcanic craters. Each of these phenomena testifies to a long and eventful geological history continent, the bowels of which are still active in the form of active volcanoes and geysers.
Geography of North America
A significant part of the mainland is still of Precambrian origin, which makes it one of the most geologically ancient regions of the Earth. First of all, this statement refers to the territory occupied by modern Canada.
Such an ancient origin of the continent makes it possible to determine the characteristics of the relief and minerals of North America as extremely diverse. The so-called Canadian shield contains extremely extensive deposits of nickel, copper, zinc, lead, gold and uranium, the reserves of which the country is on a par with Russia and the United States.
A special place in the relief of North America is occupied by the Sudbury field, located in the Canadian province of Ontario. This deposit did not appear as a result of a natural geological process, but under the influence of a fall large meteorite, which left behind a huge crater.
US territory
Various landforms of North America are represented quite widely in the United States. Among professional geologists, it is customary to divide the entire territory of the United States into five large regions, different from each other in the way of formation and time of origin.
The list of US geological provinces is as follows:
- Canadian shield.
- Cordillera.
- stable platform.
- Coastal plain.
- Appalachian fold belt.
It should be borne in mind that the provinces are spread over vast distances and, for example, the Cordillera province stretches from Tierra del Fuego in the south to the state of Alaska in the north. At the same time, Hawaii is one of the youngest parts of America in geological terms, their formation ended a little over two million years ago.
It is worth noting that the landforms of North America were formed, including with the participation of a large number volcanoes, as the entire Cordillera zone is characterized by high volcanic and seismic activity.
Geology of Mesoamerica
Although Central America is singled out as a separate region with its own characteristics, from a geological point of view it is an integral part of the North American continent. Volcanoes occupy a special place in the formation of large landforms in North America and the Isthmus of Panama.
For example, most high point Central America It is considered a stratovolcano Tahumulco, whose height reaches 4200 meters. It is also worth noting that along the southwestern coast of North America, the relief is distinguished by a significant number of active volcanoes that formed already in historical time. These include Atitlan, Poas, Irazu and Cosiguina.
In this part of the mainland, a description of the relief of North America cannot do without mentioning significant reserves of silver and gold ores. As well as huge hydrocarbon deposits, which are of particular importance in modern world, especially in the region where their largest consumer, the United States, is located.
A feature of the southern part of the relief of North America is the mountainous nature of the terrain, which affects not only the macroclimate, but also the hydrology of the entire region. Significant elevation changes affect the movement of air masses, which, in turn, provide a year-round high water flow due to moisture condensation at significant heights.
Cordillera North America
The relief of the western part of the United States is formed mainly by a mountain system that stretches along the entire coast for more than nine thousand kilometers. It is impossible to overestimate the importance of this ridge for the climate and nature of the United States. Suffice it to mention such rivers as the Colorado, Rio Grande, Missouri, Columbia and Yukon - they all have their sources in the Cordillera.
In the mountains, important mineral deposits are being developed and timber is harvested. However, tourism can compete with the mining industry in this region in terms of profitability, which is represented by both sports routes and sightseeing tours, because many landscapes, such as the Rocky Mountains, are well known to travelers around the world.
It is in the Cordillera that the highest point in North America is located - Mount Denali, whose height reaches 6193 meters above sea level. This peak belongs to the Alaskan mountain range, which forms the northwestern outskirts of the Cordilleras. One of the oldest parts of this mountain belt is the Southern Sierra Madre range, stretching for almost a thousand kilometers along the southern coast of Mexico.
great plains
An integral part of the Cordillera is the piedmont plateau, stretching across Canada and the United States east of the Rocky Mountains. The plateau is called the Great Plains because of its vastness, because it extends over the territory of three Canadian provinces and nine American states.
The height of the plains ranges from seven hundred to one thousand eight hundred meters above sea level, and the length of the entire region from north to south is about three thousand six hundred kilometers. At the same time, the width of the plains reaches eight hundred kilometers.
The description of the relief of North America inevitably includes mention of the prairies, which constitute the most recognizable part of the Great Plains. A sharply continental climate and steppe vegetation form an environment unsuitable for traditional farming, especially the so-called badlands - bad lands where rocks have undergone significant erosion.
However, the industrious settlers managed to establish such an efficient wheat production in the area that now the Great Plains are often called the world's breadbasket. Another important component of the region's economy is grazing, which is actively developing after the purchase of these lands from France.
Central Plains
To the west of the Great Plains, in the very depths of the North American continent, are the Central Plains, whose height above sea level does not exceed five hundred meters. The relief of North America shows its diversity even within this geographical region.
The landscape of the plains ranges from lacustrine and outwash in the north to karst and erosive in the south, where the plains smoothly turn into the Mexican Lowland, which defines the geography of the Gulf of Mexico coast.
The main rock that makes up the plains in this part of America is limestone. On the Central Plains, there are several ways of its occurrence - horizontally or in the form of gentle slopes. Other minerals that are characteristic of the relief of the North American mainland in this part include oil, coal, salt and natural gas.
In terms of hydrology, most of the rivers that drain the plains belong to the basin of the great Mississippi River, which forms the largest river network in North America. Large lakes in the north of the region testify to an ancient glaciation, which also had a significant impact on the relief of North America.
Great Lakes
Numerous lakes in the northeastern part of the American continent are one of the most recognizable natural objects in the United States and Canada, without which it is impossible to imagine a story about the major landforms of North America.
The Great Lakes are one of the world's largest reservoirs of fresh water, along with Lake Baikal and the glaciers of Greenland and Antarctica. All the lakes of the system are interconnected by rivers and canals, and therefore water regularly flows from one lake to another. The lakes are connected to the ocean by the St. Lawrence River, which cuts its way through the rocks, forming a picturesque landscape throughout its entire course.
The five largest lakes are the Great Lakes: Superior, Huron, Michigan, Erie and Ontario. All lakes are interconnected by rivers and canals, and the construction of additional artificial hydraulic structures made it possible to create a transport route with a length of more than three thousand kilometers, along which ocean-going ships can go.
Geography of Mexico
The entire southern part of the mainland is occupied by the Republic of Mexico, which is almost completely located on the North American plate, which determines the relief of North America in this part of the continent.
The relief of Mexico is formed mainly by two large mountain ranges, crossing the country from north to south - Sierra Madre East and Sierra Madre West. In addition, the famous volcanic belt stretches from the west to the center of the country, in which the highest peaks of Mexico are located. With a kind of fiery arc, this belt, considered one of the largest on Earth, connects the Gulf of Mexico and the Pacific Ocean.
However, despite the presence of extreme peaks and canyons, most of the country is occupied by the Mexican Highlands, located between the Sierra Madre East and the Sierra Madre West. In its eastern part, the highlands abruptly break off at the coast of the Gulf of Mexico, forming picturesque steep banks.
The main part of the highlands has a height of one thousand to two thousand meters above sea level and is represented for the most part by arid lands. Although the highlands are located in the lower latitudes, which are characterized by a warm climate, its exposure to the cold air masses of the north makes the climate in the region cold and dry in winter. Thus, temperatures in a large part of Mexico can range from -10 to +40.
Greenland
On the opposite side of the mainland, on the Canadian Shield, is the island of Greenland, which from a geological point of view also belongs to North America. Most of the island's territory is covered by an ice sheet that appeared in anthropogenic time.
Since 81% of the territory of Greenland is covered with ice, it makes sense to talk about the characteristics of the ice sheet. Its average thickness is about 2400 meters, while the maximum reaches three and a half thousand meters.
However, the ice sheet is not a static formation. Under the influence of its own mass and gravity, it moves from the center of the island to the coast, forming the so-called outlet glaciers, the speed of which can reach 40 meters per day. Upon reaching the ocean, glaciers break, forming icebergs.
Alaska
At the northwestern tip of the mainland is the Alaska Peninsula, the entire territory of which is occupied by the US state of the same name. Alaska is separated from the Eurasian continent by the Bering Strait, the width of which does not exceed 86 kilometers.
One of the most remarkable landforms of the North American mainland in this region is the Novarupta volcano. As well as the Valley of Ten Thousand Smokes, which arose in 1912 as a result of a volcanic eruption.
Thus, giving a description of the relief of North America, it is worth saying that all possible forms of landscapes are represented on the territory of the continent: from arid deserts to icy wastelands, from the rain forests of the West Coast to the steppe landscapes of the central part of the mainland.
North America. Relief and climate. The third largest continent, with an area of 20.36 million km2- located entirely in the Northern Hemisphere. The northern part of the mainland is located far beyond the Arctic Circle, the tropic passes in the south. North America is separated from South America by the Panama Canal, and from Eurasia by the Bering Strait.
The coast of North America is washed by the Pacific Ocean - in the west, the Arctic Ocean - in the north, the Atlantic Ocean - in the east. The coastline is strongly dissected in the northwest, north and northeast. The elements of the coastline are: bays- Hudson, Mexican, Californian; peninsulas– Florida, California, Alaska, Labrador; major islands– Greenland, Newfoundland, Canadian Arctic Archipelago, Greater and Lesser Antilles, Aleutian Islands.
Relief and geological structure.
The relief of the mainland is diverse and relatively compact with mountains in the west and southeast and plains in the north and center. Most of the plains of the mainland formed on the ancient North American Platform; a vast flat area in the north formed within the Canadian Shield. The northern parts of the plains have pronounced traces of glaciation - hills, ridges. The chain of the Great American Lakes is, as it were, the boundary of the glacier. To the south are the Central Plains 200-500 m high, formed by continental and marine sediments. To the west of them are the Great Plains, which are a system of plateaus 500-1700 m high, with a flat surface divided by ledges. They are composed of sedimentary rocks of continental and marine origin. South of the Central Plains is Mississippi lowland up to 100 m high. This is a flat plain formed by river sediments, bordering the coast of the Gulf of Mexico. The Mississippi Lowland is crossed by numerous rivers flowing from the Central and Great Plains, the Appalachians and the Cordilleras.
Appalachians, located in the east of the mainland, are low folded-block mountains (up to 200 m) with wide valleys, plateaus and plateaus. The highest point is Mount Mitchell (2037 m). A distinctive feature of the mountains is the inversion relief, i.e., the external structure does not correspond to the tectonic structures that underlie the relief forms.
The main mountain system of North America - Cordillera stretched along the western edge of the mainland. Highest point - mountain McKinley(6193 m). This folded belt arose at the junction of two lithospheric plates- oceanic and continental. Active processes of mountain building are still going on here: frequent earthquakes and volcanic activity. The largest volcanoes Orisabo, Katmai. In the Cordillera, two chains of mountain ranges stand out: the Cordillera proper and the Rocky Mountains. Actually the Cordilleras are huge arcs that border the oceanic depression; ridges and plateaus here are crossed by tectonic faults. In the Rocky Mountains, post-volcanic phenomena are observed in the area yellowstone national park - geyser eruptions, thermal springs, mud volcanoes. Between the chains of mountain ranges, a system of plateaus and uplands is formed: the Yukon Plateau (within Alaska), the Fraser Volcanic Plateau (in Canada), the Columbian Plateau, the Great Basin, and the Colorado Plateau.
Climate.
The diversity of the climate of the mainland depends on its position in different latitudes. North America is located in all climatic zones, except for the equatorial one. Another important climate-forming factor is the relief of the mainland. Large meridional mountain systems contribute to the penetration of cold arctic air far to the south and tropical air masses to the north. In internal parts mainland formed continental climate. The climate is also influenced by ocean currents: cold - Labrador and California - lower the temperature in the summer, and warm - the Gulf Stream and the North Pacific - increase the temperature in winter and increase the amount of precipitation. However high mountains in the west hinder the penetration of air masses from the Pacific Ocean.
Within arctic climate zone are the northern margin of the mainland and most of the islands of the Arctic Ocean. In winter, the temperatures here are very low, snow storms are frequent, and cover glaciation is developed. Summer is cold, short, the air warms up to +5 °C. The average annual rainfall is less than 200 mm.
Subarctic climate zone covers the territory between the Arctic Circle and 60 ° N. sh. In the west, the belt extends below the latitude of Moscow. This is due to the influence of the Arctic Ocean, the cold Labrador Current and the northeast winds from Greenland. There are oceanic and continental types of climate. In winter, the temperature reaches -30 °C, near the coast of the oceans the temperature ranges from -16 to -20 °C. Summer temperatures are 5-10 °C. The amount of precipitation varies from 500 mm per year in the east to 200 mm per year in the west (Alaska region).
Most of the mainland is located within temperate climate zone .
It distinguishes three climatic regions:
- region temperate maritime climate in the west of the mainland (the Pacific coast and the western slopes of the Cordillera). Westerly transport dominates here: winds bring a large amount of precipitation from the ocean - up to 3000 mm per year. The average temperature in January is up to +4 °С, the average temperature in July is up to +16 °С;
- region located in the central part of the belt. It is characterized by relatively warm summers - from +18° to +24°С; cold winter - up to -20 ° С. The amount of precipitation in the west is up to 400 mm, but their amount increases to 700 mm in the east. The practically open space of this part of the mainland is subject to the invasion of air masses from both the north and the south. Therefore, atmospheric fronts are frequent here, accompanied by snow storms in winter and showers in summer;
- region temperate continental climate distributed along the east coast of the Atlantic Ocean. In winter, cyclones are frequent here, bringing a lot of snow; temperature from -22 °С in the north to -2 °С in the south. Summer is not hot - up to +20 ° С; the cold Labrador current has its influence. The amount of precipitation is different, depending on the relief and distance from the ocean, but on average - 1000-1500 mm per year.
Subtropical climate zone located on the territory from 40 ° N. sh. to the coast of the Gulf of Mexico. The territory also has a large extent from west to east, so there are differences in climate types and the following climatic regions are distinguished:
- in the West subtropical mediterranean climate with warm and humid winter: temperature +8 °C, rainfall up to 500 mm per year; and dry, cool summers: temperature +20 °С - the cold California current has its effect;
- region subtropical continental climate located in the center of the climate zone. Characterized by high temperatures in summer and low rainfall throughout the year;
- region humid subtropical climate covers the Mississippi lowlands. Summer temperatures up to +30 °С, mild winters up to +5 °С.
South of 30° N. sh. located tropical climate zone , it is hot all year round. On the east coast of the mainland and on the islands, there is a large amount of precipitation brought by the trade winds. The California Peninsula has a dry tropical climate.
Subequatorial climate zone located on the narrowest southern part of the mainland. Here, typical for this climatic zone, high temperatures during the year are about +25 °С. Winds from the Pacific and Atlantic Oceans bring a lot of moisture - up to 2000 mm per year.
Land waters.
North America has large full-flowing rivers, numerous lakes and significant groundwater reserves. In terms of annual runoff, the mainland is second only to South America. The river network is unevenly distributed over the mainland, and the rivers have different types nutrition.
home river system mainland Mississippi with inflow Missouri has a length of 6420 km, and carries its waters to the Gulf of Mexico. The river basin includes the Rocky Mountains, the Appalachians, the Central and Great Plains. The river is full-flowing all year round and has snow and rain types of food. The rivers of the Pacific basin have a large steepness of fall, so they are turbulent, rich in hydropower. Among them major rivers Colorado(2740 km) and Colombia(2250 km). River Yukon in northwestern Alaska, it is full of water in the summer, during the snowmelt period. The largest river in the Arctic Ocean basin Mackenzie 4250 km long originates in the Great Slave Lake.
Most of the lakes in North America are located in areas that have undergone glaciation. The most unique system great lakes- Upper, Huron, Michigan, Erie, Ontario - the world's largest accumulation of fresh water on land. Most of the lakes are of considerable depth, for example, Lake Superior is almost 400 m deep. Lakes Erie and Ontario are connected by the Niagara River. Cutting through a hilly ridge, the river overthrows the Niagara Falls, 50 m high and 1 km wide.
Major lakes in North America are also Winnipeg, Great Slave, Great Bear, Athabasca. Residual lakes have been preserved in the basin of the Great Basin - the Great Salt, Utah.
Summary of the lesson “North America. Relief and climate.
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North America is the third largest among the 6 continents of the planet Earth and is located in the north of the Western Hemisphere. The area of the entire continent, excluding nearby islands, is approximately 20.36 million km2 (with islands 24.25 million km2), which is approximately 14% of the total land area of the planet.
There are 23 states on the territory of the mainland. If you follow the link, you can see a complete list of countries and dependent states on the territory of the North American continent. And the population is approximately 500 million people, which is approximately 7% of the total number of people on planet Earth.
The mainland of North America is washed in the south by the Caribbean Sea, the Atlantic and Pacific Oceans, in the west the coast of the mainland is washed by the Pacific Ocean, in the north the coast of the mainland is washed by the Arctic Ocean, and in the east the coast of the continent is washed by the Atlantic Ocean.
The length of the continent from north to south is 7326 km, and from west to east about 4700 km. North America and South America are separated by the Isthmus of Panama, and North America and Eurasia by the Bering Strait.
Extreme points of mainland North America
Extreme points of North America, which are located on the mainland:
1) The northernmost point on the mainland is Cape Murchison, which is part of the Kitikmeot region.
2) The westernmost point of the mainland is Cape Prince of Wales, which is located on the Seward Peninsula in Alaska. An interesting fact is that this cape and the extreme continental point in the west of Eurasia (Cape Dezhnev) are separated by a distance of only 86 kilometers.
3) extreme point the mainland in the south is Cape Mariato, which is located on the Azuero Peninsula.
4) The extreme eastern point of the continent is Cape St. Charles, which is located on the Labrador Peninsula.
Relief of North America
The central part of the mainland of North America has many mountain ranges, of which the longest can be distinguished - the Cordillera de Talamanca, the Sierra Madre de Chiapas and the Cordillera Isabella. And between these mountain ranges are fertile valleys, where the bulk of the population of Guatemala, Honduras and Costa Rica lives.
In the east of the continent is the Appalachian mountain system, also on the mainland there are the Rocky and Cascade Mountains, the Cordillera Mountains.
On the territory of the mainland there are the Great Plains - this is a foothill plateau, which is located to the east when viewed from the Rocky Mountains, the Central Plains - plains that are located in the inner part of the mainland, as well as coastal lowlands. The height of the coastal lowlands does not exceed 200 meters, and in the coastal zone they are expressed as lagoons, bars, beaches and spits.
The central part of the mainland is characterized by rather high seismic activity, which is expressed in the form of volcanic eruptions and earthquakes.
Mount Denali is considered the highest point of the continent (until 2015 it was called McKinley), and the lowest point of the mainland is Death Valley, which is located at a level of 86 meters below sea level.
Climate of North America
The mainland of North America is located in the north in the western hemisphere, thus, the climate on the mainland varies from arctic to subequatorial. At the same time, the coastal regions of the continent have an oceanic climate, while the interior regions of the continent have a continental climate.
Since the mainland stretches from north to south for more than 7000 km, on the continent you can find all types of climate on the planet, except for the equatorial one. It is thanks to this that the animal and plant world of North America is so rich.
If you look at temperatures, then in the northernmost part of the mainland in winter the average temperature is -36 degrees Celsius, and in summer +4 degrees Celsius. At the same time, in the southernmost part of the mainland, the average temperature in winter is +20 degrees Celsius, and in summer +32 degrees Celsius.
The arctic climate is located in the northernmost part of the mainland. It is characterized by very cold winters and the almost complete absence of summer. On the hottest days, temperatures can rise slightly above 0 degrees Celsius.
This is followed by the subarctic zone, which is also characterized by very cold winters, but there is already a short-term summer. Somewhere in June, the snow begins to melt and the weather stays warm for about a month. In summer the temperature can reach up to +16 degrees Celsius. In winter, approximately -24-40 degrees Celsius, winters are very long and cold, the maximum part of precipitation falls in summer.
The temperate zone covers the northern part of the United States and the southern part of Canada. The western part of the mainland in this belt is characterized by cool summers (+8+16 degrees Celsius) and relatively warm winters (0-16 degrees Celsius). In the central part of the mainland of this belt, the climate is very different. It is characterized by warmer summers (+16+24 degrees Celsius) and colder winters (-8-32 degrees Celsius). The eastern part of the mainland in this belt has warm summers (+16+24 degrees Celsius) and warm winters (0-16 degrees Celsius).
The subtropical zone is located in the southern United States and northern Mexico. This zone is characterized by hotter summers and warmer winters. The central part of the mainland, which is located in the subtropical zone, has proven itself adverse conditions climate. There is a problem of desert growth and climate dryness.
The tropical climate covers the central part of North America. It is characterized by hot summers (+16 to +32°C) and warm winters (+8 to +24°C). There is little rainfall.
The subequatorial belt occupies a small area in the very south of the continent. The climate here is hot. For all year round The air temperature stays above 20 degrees. Precipitation is plentiful and mostly in summer.
Inland waters of North America
The North American continent is rich in both rivers and lakes. The longest river system in North America is the Mississippi River. Its length reaches 3770 kilometers. The largest reserves fresh water on the mainland are concentrated in the Great Lakes. The Great Lakes include five large lakes: Michigan, Superior, Huron, Ontario and Erie (sometimes a sixth lake, St. Clair, is added), the total area of \u200b\u200bwhich is approximately 244,106 kilometers.
All rivers of the mainland North America belong to the basins of the Arctic, Pacific and Atlantic oceans.
The territory of the mainland is irrigated rather unevenly. This is due to several reasons, including climatic and orographic. Most of the mainland's rivers have both transport and hydropower significance.
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Geological structure of North America
At the base North America and most Greenland lies the Precambrian North American platform, which is sometimes called Canadian. The foundation of the platform in some places goes to surface, forming Canadian-Granland Shield. The shield formed by faults consists of metamorphosed volcanic rocks and granite gneisses of the Archean Early Proterozoic age. Grenville Belt, which stretches in the southeastern part shield, formed by Early Precambrian rocks and metamorphosed Proterozoic carbonate-clastic formations.
As geophysical studies and drilling data show, the basement, covered with a sedimentary cover, is also composed of Early Precambrian metamorphosed sedimentary-volcanic rocks and granite-gneisses. In the building rocky mountains USA viewed Early Precambrian crystalline rocks. Sedimentary cover platform extends south, west and north of the Canadian Shield, and its greatest area observed in the region Midcontinent and Great Plains. The depth of the foundation changes, so a number of large hollows – syneclise, with a depth of $3$-$4$ km and vaults – anteclise. Part of the platform in the southwest dissects moving zone mountains washita.
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In the meridian Great Plains continued into the Mesozoic subsidence and accumulation coastal-marine and continental precipitation. Finally, marine sediments were displaced by continental ones at the beginning cenozoic era, followed by a complete platform drainage.
Paleozoic cover platforms in addition to the Midcontinent and the Great Plains extends to Arctic her slope. Here it forms the southern part of the Canadian Arctic archipelago. Shallow but big syneclise Hudson Bay is filled with formations similar in composition and age. Its central part is thin continental precipitation jura and chalk.
Caledonides Northeast Greenland are the most ancient link folded framing of the North American platform. In the form of tectonic covers, they are pushed over the edge of the platform, and are composed of a thick layer of sedimentary terrigenous-carbonate rocks of the Lower Paleozoic. Along the fault, the so-called logan line, the fold system of Newfoundland and the Northern Appalachians border the Canadian Shield.
Line Logan represents thrust geosynclinal Paleozoic strata to platform Paleozoic and Precambrian. Narrow grabens with continental sediments and basaltic lavas are also present in Northern and Southern Appalachian. This is evidence that before entering the platform stage of development, the Appalachian system was fragmented.
Zone Hercynian folding within the coastal lowlands - from the Gulf of Mexico - blocked by powerful Cenozoic deposits. System Canadian Arctic Archipelago and north Greenland related to Hercynian folding, are composed of terrigenous-carbonate deposits of the Cambrian-Devonian.
Folded Cordillera belt, located along the Pacific coast, almost along its entire length borders on North American platform, with the exception of Alaska. Here this belt is limited by the ridge system Brooks. Along the Pacific coast is the main seismically active zone of North America.
Remark 1
The zone is characterized by destructive earthquakes- Alaskan ($1964), Mexican ($1985), San Francisco ($1906). In the future, this area is still seismic, especially in those places where it intersects with the latitudinal transform faults of the Pacific Ocean.
Relief of North America
The relief of North America is characterized by a fairly large variety and contrast.
To replace almost flat plains in the central part of the mainland come extensive rolling expanses, neighboring in the east with low Appalachians.
To the west, the Central Plains adjoin Cordillera. The peaks of these mountain structures are sharp and reach a height of more than $6000 m. The relief of the mainland and its features are connected with history. geological development territory. Ancient The North American Platform and its crystalline basement formed over the course of Archean and Proterozoic eras. Canadian Crystal shield in relief corresponds Laurentian elevation.
On the stove, located south of the Canadian Shield, are Central and Great Plains. The Great Plains stretch from north to south for $3500$ km and are located in the western part of the platform. Their height reaches $1500$ m, which can be explained by powerful uplifts earth's crust in the region of the Cordillera folding.
south of Laurentian hills are located Central Plains. In the south of the mainland are Mexican and Atlantic lowlands formed on the foundation of a young platform covered with a layer of sedimentary deposits. Appalachians are old, ruined mountains, with smoothed and low ridges. Folding in them occurred in the Caledonian and Hercynian periods.
In the west of the mainland, grandiose folding began as early as mesozoic era as a result of the collision of lithospheric plates and continues to the present. Arising here Cordillera stretched in the meridional direction for $9000$ km, with a width of $1600$ km.
The mountains do not end in the south of the mainland, but continue into South America. The peak of the Cordillera is the mountain McKinley, whose height is $6193$ m. Numerous faults of the Pacific ocean floor continue in the Cordillera ranges. The mountains are characterized by the largest volcanoes planets - Popocatepetl and Orizaba.
Remark 2
Not only internal but also external processes took part in the formation of the relief. The northern regions of the mainland up to the $40$ parallel were covered glacier, which in its size exceeded the area of Australia by $2$ times. The movement of the glacier leveled the surface, polished even the rocks. The glacier created thousands of long hills and many small landforms.
In addition to the glacier, active participation in the formation of the relief took surface water, groundwater and wind. For example, the work of the river Colorado created Grand Canyon, the depth of which is $1600$ m, and the length is $400$ km. The largest on the planet Mamontov a cave was formed underground water, and activities wind led to the emergence of dunes, dunes and other landforms.
Minerals of the mainland
Subsoil of North America rich in minerals and related to its geological structure. The biggest in the world ore deposits occur in the area Canadian Crystal Shield where igneous and metamorphic rocks are shallow. The largest deposits are concentrated here iron, nickel, copper, uranium, molybdenum.
Coal located in a thick layer of sedimentary rocks Central Plains, and coastal lowlands and shelf seas have large deposits oil and gas. Hydrocarbon production is carried out both onshore and from the day Mexican bay. The intermountain depressions of the Appalachians also have significant reserves stone coal.
AT Cordillera large mineral deposits of both igneous and sedimentary origin are concentrated. There is non-ferrous metal ores, gold, mercury. In the east and in the trough of the earth's crust between Cordillera and North American Platform lie oil, gas, coal. Significant reserves and diverse minerals are an important natural resource base for the development of the economies of the countries located on this continent.
Relief of North America predominantly flat, because most of it lies within platforms. The western and eastern parts of the mainland were formed at different geological times - western part in Mesozoic and Cenozoic, a eastern part - in Paleozoic.
Remark 3
The ancient and ruined Appalachians are located in the east of the mainland, and the high and young Cordilleras are located in the west. associated with the peculiarities of the geological structure. wealth and diversity minerals of the mainland. And such minerals as coal, oil, natural gas, iron, nickel, molybdenum ores and uranium have global importance.
